1. Field of the Invention
The present invention generally relates to electronic components, manufacturing methods of the electronic components, electronic component assembly bodies, and electronic devices, and more specifically, to an electronic component such as an LED (light emitting diode), a manufacturing method of the electronic component, an electronic component assembly body having the electronic component, and an electronic device having the electronic component assembly body.
2. Description of the Related Art
For example, as electronic components emitting light, light emitting components such as a LED (Light Emitting Diode) diode or a laser diode have become known. These electronic components are mounted on boards. Japanese Laid-Open Patent Application Publication No. 5-129711 describes a semiconductor laser device where a semiconductor laser chip is mounted. In this semiconductor laser device, laser light emanates from the semiconductor laser chip in a direction parallel (horizontal) with a surface direction of chip mount (board). In addition, the laser light emanating in this horizontal direction is converted at 45 degrees by a reflection mirror so as to irradiate in a direction perpendicular to the chip mount.
FIG. 1 is a perspective view of a first related art component mounting board. More specifically, in the example shown FIG. 1, a component mounting board 1A where an electronic component 3 is mounted on a board 2 is shown. The electronic component 3 includes a semiconductor laser chip 9 and leads 5. The leads 5 extend to sides of the semiconductor laser chip 9. Pads 4 are formed on a mounting position of the electronic component 3 of the board 2. The electronic component 3 is mounted on the board 2 by soldering the leads 5 to the pads 4. A light emitting surface 8A of the electronic component 3 faces upward and therefore the laser light is irradiated upward.
However, in the structure shown in FIG. 1 where the electronic component 3 is surface mounted on the board 2, a projecting amount shown by an arrow “h” in FIG. 1 from a board surface 2a of the board 2 of the electronic component 3 is high, so that thickness of the entire component mounting board 1A is large. While the projection height from the board surface 2a of the electronic component 3 is approximately several mm through several tens mm, in a case where the electronic component 3 is mounted on an electronic device such as a portable phone required to have small size and thickness, a dead space may be formed inside of the electronic device or interference with other components may be generated.
Because of this, as discussed in Japanese Laid-Open Patent Application Publication No. 8-186326, a structure where an opening is formed in a board and an electronic component is inserted in the opening at the time of mounting so that thickness of entire component mounting board can be made small has been suggested. FIG. 2 is a perspective view of a second related art component mounting board and shows such a mounting structure.
As shown in FIG. 2. an opening part 6 is formed in a board 2. Pads are formed in the vicinity of the opening part 6. The electronic component 3 is mounted on the board 2 in an inverted state where a light emitting surface 8A faces downward and a rear surface 8B faces upward. Under this structure, since the electronic component 3 is positioned in the opening part 6 and does not project from the surface of the board 2, it is possible to make the entire component mounting board 1B have small thickness.
However, in the mounting structure shown in FIG. 2 where the electronic component 3 is simply made up side down and inserted in the opening part 6, depending on the thickness of the board 2 where the electronic component 3 is mounted, problem discussed below may be generated.
FIG. 3 is a perspective view for explaining the problems of the example shown in FIG. 2. More specifically, FIG. 3(A) shows a component mounting board 1B having a thick board 2 where an electronic component 3 is mounted. FIG. 3(B) shows a component mounting board 1C having a thin board 2 where the electronic component 3 is mounted. The thickness D1 of the board 2 shown in FIG. 3(A) is greater than the thickness D2 of the board 2 shown in FIG. 3(B) (D1>D2).
In the case shown in FIG. 3(A) where the thickness D1 of the board 2 is large, namely the opening part 6 is deep, the light emitting surface 8A of the electronic component 3 is positioned at a deep point inside of the opening part 6 separated from the rear surface of the light emitting surface 8A. Therefore, even if light L1 is irradiated from a deep position of the opening part 6, the spread of the light L1 is blocked by an internal wall of the opening part 6 so as to be narrow.
On the other hand, in the case shown in FIG. 3(B) where the thickness D2 of the board 2 is small, namely the opening part 6 is shallow, the light emitting surface 8A of the electronic component 3 is positioned in the vicinity of the rear surface of the board 2. Therefore, in a case where light L2 is irradiated from a position in the vicinity of the rear surface of the board 2 of the opening part 6, the amount of the light L2 blocked by the opening part 6 is small and therefore the spread of the light L1 is wide.
More specifically, if the electronic components 3 are provided at the same heights in the examples shown in FIG. 3(A) and FIG. 3(B), the spread W1 (calculated as a diameter of irradiated light) of the light L1 in the example shown in FIG. 3(A) where the thickness of the board 2 is large is narrower than the spread W2 (calculated as a diameter of irradiated light) of the light L2 in the example shown in FIG. 3(B) where the thickness of the board 2 is small.
Thus, in the structure where irradiation characteristics of the light irradiated by the electronic component 3 are changed depending on the thickness of the board 2, since a light irradiation amount of the light emitting diode chip 9 is changed depending on a plate pressure of the board 2, it is not possible to obtain stable characteristics. In addition, it is necessary to change the characteristics of the light emitting diode chip 9 corresponding to the depth of the opening part 6 depending on the plate pressure of the board 2. Hence, in this case, a large amount of time, workload or cost may be required for change of setting.